MSDN and Technet runs on Hyper-V

The MSDN and Technet websites have now been fully migrated to running within virtual machines on a Hyper-V platform.

These are 2 of the most visited sections of microsoft.com, with 4 million hits per day - quite a lot of user activity I'm sure you'll agree.

More info at http://www.virtualization.info/2008/05/microsoft-migrates-msdn-and-technet-on.html